The present invention relates to a double articulated material handling machine that is particularly useful in transporting and providing stability to a rotatable working tool having a cantilevered boom arm.
It is known to mount a rotatable working tool such as a crane assembly having a cantilevered boom arm on a rigid frame machine. One of the problems with this type of machine is that special steering must be used thereby increasing the cost of manufacture. Another problem is stability because the load being worked upon is cantilevered from the main machine frame. Thus, there has been a need for a machine construction that is particularly adapted for use with a working tool having a cantilevered boom arm.
Articulated machines having a vertical pivot in the machine frame located approximately midway between the two drive axles are also known. These machines have primarily been used for front end loading shovels having the engine mounted at the rear. An advantage to this construction is that a shorter turning radius is possible by turning the front and rear axles relative to each other about the vertical pivot. However, this general type of machine has not heretofore been practical for use with rotatable working tools having cantilevered boom arms because of the need for substantial lateral stability when a load is applied to the cantilevered boom arm.
Thus, the disadvantages of prior material handling machine constructions have resulted in the double articulated material handling machine of the present invention which provides improved steering and stabilization for a rotatable working tool having a cantilevered boom arm.